FBTF: Remove unneeded headers from base/ (part 6)

BUG=none
TEST=none
Review URL: http://codereview.chromium.org/3093013

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@56641 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/net/base/cert_test_util.h b/net/base/cert_test_util.h
index b800c23..45c8ed3 100644
--- a/net/base/cert_test_util.h
+++ b/net/base/cert_test_util.h
@@ -6,9 +6,10 @@
 #define NET_BASE_CERT_TEST_UTIL_H_
 #pragma once
 
-#include "base/file_path.h"
 #include "build/build_config.h"
 
+class FilePath;
+
 namespace net {
 
 class X509Certificate;